• Which the release of FS2020 we see an explosition of activity on the forun and of course we are very happy to see this. But having all questions about FS2020 in one forum becomes a bit messy. So therefore we would like to ask you all to use the following guidelines when posting your questions:

    • Tag FS2020 specific questions with the MSFS2020 tag.
    • Questions about making 3D assets can be posted in the 3D asset design forum. Either post them in the subforum of the modelling tool you use or in the general forum if they are general.
    • Questions about aircraft design can be posted in the Aircraft design forum
    • Questions about airport design can be posted in the FS2020 airport design forum. Once airport development tools have been updated for FS2020 you can post tool speciifc questions in the subforums of those tools as well of course.
    • Questions about terrain design can be posted in the FS2020 terrain design forum.
    • Questions about SimConnect can be posted in the SimConnect forum.

    Any other question that is not specific to an aspect of development or tool can be posted in the General chat forum.

    By following these guidelines we make sure that the forums remain easy to read for everybody and also that the right people can find your post to answer it.

Disappearing objects....

Messages
1,851
Country
unitedkingdom
I've got a model of fences and vegetation, normal stuff.... but when you view it from a certain angle, the whole thing disappears, and then reappears as if you look at it from a slightly different angle.... what is going on?!:banghead:
 
Messages
1,851
Country
unitedkingdom
I think I've figured it out....
My empty LOD was showing as you view it from the angle where you're facing the backs of the double sided planes!... They obviously don't count towards the LOD calculation.... annoying as there's a lot of polys.
 

arno

Administrator
Staff member
FSDevConf team
Resource contributor
Messages
30,647
Country
netherlands
Hi,

This can happen if the bounding box of the object is wrong (too small).
 
Messages
1,851
Country
unitedkingdom
This explains why some objects, like big hangars, disappear when reaching the corner of the screen? Despite being present in 100s of pixels there.

How does one modify the bounding box?
 

arno

Administrator
Staff member
FSDevConf team
Resource contributor
Messages
30,647
Country
netherlands
Normally GMax will calculate the bounding box correctly for you. So in most case there should not be a problem.

Is this with the FSX or FS2004 gamepack? And are the objects optimized so that the reference point is in the centre of the object.
 
Messages
1,851
Country
unitedkingdom
Ah, no they aren't, the reference point is quite far away, at the edge of my background sheet. Does this affect performance? If I put the model at 0,0 I don't know what coordinates it is...
 

arno

Administrator
Staff member
FSDevConf team
Resource contributor
Messages
30,647
Country
netherlands
Hi,

Yes, I think having them very far from the reference point can influence the disappearing of the objects. It is much more optimal to have each object with a reference point that is roughly in the middle of the object.

You can then probably position the object with some placement tool. Or if you know the offset in meters you could calculate the position.
 
Messages
1,851
Country
unitedkingdom
Ok, I'm using the centre as the reference point now,

I have disappearing hangars also when they are passing out of view, yet these are placed in ADE, with the reference point at the centre of the object. I might put a simple box under ground that extends beyond the boundaries to try and fix this actually.
 
Messages
10,013
Country
us-arizona
I see this often with fences in P3D. I thought it was the sim platform doing odd things. I do not remember this happening before in FSX, though FSX did everything else crazy, lol.. (pink runways???)
 
Messages
99
Country
us-newmexico
Arno,

I have the same problem with my taxiway light models. I have created many buildings with Sketchup and ModelX conversion that work fine, so I know that process pretty well. But with these small objects, they disappear/reappear at random. Changing the view angle often brings them back. What's really odd is that only the base model disappears. The texture used to simulate the light glow does not. It stays the whole time.

My model steps are Sketchup - DAE - ModelX. I'm using both day and night textures. The model is centered on 0,0.

What are the things I need to check? You mentioned bounding box. Given than I use Sketchup - DAE, is there a way to change that?
 

arno

Administrator
Staff member
FSDevConf team
Resource contributor
Messages
30,647
Country
netherlands
Hi,

The bounding box is automatically calculated during conversion to MDL file.

Does your model include only one light or multiple instances of the light?
 
Messages
1,510
Country
unitedstates
What's really odd is that only the base model disappears. The texture used to simulate the light glow does not. It stays the whole time.

That would make me think that you've exceeded the 43690 triangle limit on a given drawcall rather than a bounding box problem. You may need to make another model that uses a renamed copy of your texture sheet and substitute that model for half of your placements.

Jim
 
Messages
99
Country
us-newmexico
Hi,

The bounding box is automatically calculated during conversion to MDL file.

Does your model include only one light or multiple instances of the light?

Hi Arno. Thanks for your reply.

There are no attached effects to the object. (I'm guessing that's what you mean by "light") The light is simulated with a semi-transparent texture on a plane - pretty much the same as you see in the various tutorials and discussions on how to make taxiway lights. It is part of the model from the beginning.

I see from what you're saying that we don't have any control over the bounding box, so that probably isn't the issue. Any other thoughts?
 
Messages
99
Country
us-newmexico
That would make me think that you've exceeded the 43690 triangle limit on a given drawcall rather than a bounding box problem. You may need to make another model that uses a renamed copy of your texture sheet and substitute that model for half of your placements.

Jim

Hi Jim. Thanks for the reply.

This is a fairly simple model made from extruded cylinders and a couple of planes. It doesn't take very many instances for the problem to occur. I placed about 30 lights last night for testing and they all disappeared/reappeared. I'll doublecheck the triangle count in ModelConverterX. I also find the idea of staggered draw calls intriguing. It increases the number of calls, which could be a framerate concern, but it is something I would never have thought of. I'll give it a shot to see what the results are.
 
Messages
1,510
Country
unitedstates
So did your lights have roughly 1450 triangles according to MCX (43690/30=1456.3)? That seems impossible but if <30 placements works and the problem starts occurring at >30 placements it must be the cause. If that's the case I think I'd look into reducing the triangle count rather than adding the drawcall, I have a fairly complex taxiway light object that's 168 triangles. Do your cylinders have many unnecessary height segments? Sketchup wants to make circles with 24 sides by default and for a taxiway light you shouldn't need more than 8 so when you make your circle before you extrude it, right click and choose entity info, there you can reduce the number of sides to 6 or 8 before you start extruding, that will have a profound effect on the number of triangles in the finished model but you won't likely be able to see the difference in the sim if you "soften edges".

Jim
 
Top